Truman and the Deep Blue Sea is an episode set directly after Martha in Charge.
It begins with Truman reading the Odyssey and imagining himself in the story. Alice asks him to get his nose out of his book and asks him what he's reading. He explains about the Odyssey and she tells him that he will see whales on a trip, handing him tickets. Truman wants to see blue whales but doesn't want to go on the trip as it's on a boat and he doesn't like boats.
Helen feeds Martha and encourages Truman to come. Truman tells Helen he gets seasick. Martha thinks that means sick of "C"s. Helen explains what seasickness means, which nauseates Truman. Helen asks if there's medicine and Truman says that there is but he's tried it but it didn't work. Martha suggests maybe he will grow out of it as she had carsickness as a puppy but doesn't have it now. Helen suggests to get Truman used to the feeling of boats.
Helen then rocks Truman in a rocking chair but that doesn't make him feel ill, it just bores him. Martha then gets a sprinkler to use as sea spray. That doesn't work, he just thinks Martha has bad breath. Martha says that it's because she ate some tuna fish.
They then practice on a fake ship at the playground but end up falling into the pond.
They then practice in a small rowboat at the beach. Truman gets nauseous, and Martha thinks he said "my nose itches". Helen explains what nauseous means and tells him to take deep breaths. Martha tells him to think of dog food, which makes him gag and then quit.
That night, he dreams that everyone else are going on the boat trip but he's still too seasick to go. Then, in the dream, Odysseus, who's done a wrong turn, tells him to overcome his nausea. Then, the cyclops shows up and chases Truman, who's feeling ill, into a boat. Truman then wakes up, having jumped off the bed in his sleep.
On the day of the boat trip, Alice is looking forward to seeing dolphins. Truman then shows up late.
They go on the trip, but Truman, despite not feeling sick, doesn't want to move for fear of getting seasick. Helen then thinks she's seen a whale, but it was a mistake. Alice then serves up sandwiches, which she drops one of, which Martha eats. Truman starts to get seasick. Alice offers pea soup and Truman tries to read to see if that would cure his seasickness, but it doesn't work so he goes downstairs to lie down. He watches a pencil, complaining, when he hears Helen point something out. Truman comes up, asking where the whale is, and Martha says that they were watching a person juggling four oranges. Truman then joins in with his friends who are playing go fish. Truman then gets a bit dizzy and wants to throw up, but this feeling goes away when he sees a whale. He then cheers up.
That evening, still on the boat, Truman talks about whales, while Martha grosses them out by talking about eating trash.
- Carolina, Milo, and T.D. were absent from the trip.